In radar range tracking systems for measuring time alignment error of an input signal, an early-late gate is generated to aid in sensing arrival time of the signal. FIG. 1 discloses a typical conventional early-late gate. RF (radio frequency) input pulses are coupled simultaneously into first and second channels having amplifiers 1 and 2 and RF switches 3 and 4 respectively. Amplifier 2 provides a phase reversal to that of amplifier 1. A summer 5 combines the channel outputs and provides the combined early-late gate. Video pulses are used to gate switches 3 and 4, the pulse to switch 4 beginning simultaneously with the ending of the pulse to switch 3. Any RF energy occuring during the pulse to switch 3 is amplified and gates into the summer, while any RF energy occuring during the pulse to switch 4 is inverted before being gated to the summer. This conventional method requires separate amplifiers/inverters, RF switches and summing circuitry.
A time alignment error sensor system is disclosed in U.S. Pat. No. 4,083,048 issued Apr. 4, 1978 to Robert J. DeRosa and Robert T. Campbell, the inventor of the instant invention. This system discloses the use of both a normal and split gate in determining time alignment error. Quadrature summing of the signals allows the time alignment error to be encoded as a phase angle which allows error decoding between incoming RF pulses and time reference for range tracking.